There exists a class of torsional vibration dampers of the kind in which radially disposed springs in chambers containing damping fluid interconnect coaxial inner and outer components which are rotatable relative to one another to flex the springs and achieve a damping effect. An example of this type of damping is described in U.S. Pat. No. 3,996,767 to Geislinger. This device comprises a hub integral with an output/input shaft. The hub and a clamping ring define therebetween an annular damping chamber defined at one end face by a coupling flange and at the other end face by a cover plate. Angularly spaced groups of flexible leaf springs are arranged in this chamber and extend radially between the hub and the clamping ring which locks the leaf springs in position. The leaf springs are radially inwardly tapered and a plurality of intermediate wedge-shaped elements are arranged between respective groups of leaf springs. The leaf spring groups and the wedge-shaped elements are assembled by placing the clamping ring around them in tension.
This type of coupling is expensive because it requires complex assembly of many parts which must be premachined to high tolerances. In particular, the groups of springs, wedge-shaped elements and clamping ring must all be accurately positioned relative to each other and the central hub. This type of damper is assembled by placing the wedges, springs and necessary shims to form a ring and then placing an outer clamping ring over the assembly of individual parts. The clamping ring serves the purpose of clamping the outer ends of the springs so it must either be heat shrunk onto the periphery of the assembly or incorporate a design which allows it to be urged inwardly. Since there are a multiplicity of individual components, any inaccuracy will be magnified because of the stack-up of tolerances. As a result, the hoop stress of the clamping ring can rise to a level where cracking of the ring could occur.
It is an object of the present invention to obviate or mitigate the aforesaid disadvantage.